Thread (2 messages) 2 messages, 2 authors, 2016-01-25
STALE3833d

[PATCH] crypto: drbg - remove FIPS 140-2 continuous test

From: Stephan Mueller <hidden>
Date: 2016-01-22 08:53:56
Also in: lkml
Subsystem: crypto api, the rest · Maintainers: Herbert Xu, "David S. Miller", Linus Torvalds

Hi,

the following patch is fully CAVS tested on 64 bit and 32 bit.

Note, this change cannot be made for random.c or ansi_cprng.c, unfortunately.

---8<---
The newly released FIPS 140-2 IG 9.8 specifies that for SP800-90A
compliant DRBGs, the FIPS 140-2 continuous random number generator test
is not required any more.

This patch removes the test and all associated data structures.

Signed-off-by: Stephan Mueller <redacted>
---
 crypto/drbg.c         | 64 ---------------------------------------------------
 include/crypto/drbg.h |  4 ----
 2 files changed, 68 deletions(-)
diff --git a/crypto/drbg.c b/crypto/drbg.c
index ab6ef1d..1b86310 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -220,48 +220,6 @@ static inline unsigned short drbg_sec_strength(drbg_flag_t flags)
 }
 
 /*
- * FIPS 140-2 continuous self test
- * The test is performed on the result of one round of the output
- * function. Thus, the function implicitly knows the size of the
- * buffer.
- *
- * @drbg DRBG handle
- * @buf output buffer of random data to be checked
- *
- * return:
- *	true on success
- *	false on error
- */
-static bool drbg_fips_continuous_test(struct drbg_state *drbg,
-				      const unsigned char *buf)
-{
-#ifdef CONFIG_CRYPTO_FIPS
-	int ret = 0;
-	/* skip test if we test the overall system */
-	if (list_empty(&drbg->test_data.list))
-		return true;
-	/* only perform test in FIPS mode */
-	if (0 == fips_enabled)
-		return true;
-	if (!drbg->fips_primed) {
-		/* Priming of FIPS test */
-		memcpy(drbg->prev, buf, drbg_blocklen(drbg));
-		drbg->fips_primed = true;
-		/* return false due to priming, i.e. another round is needed */
-		return false;
-	}
-	ret = memcmp(drbg->prev, buf, drbg_blocklen(drbg));
-	if (!ret)
-		panic("DRBG continuous self test failed\n");
-	memcpy(drbg->prev, buf, drbg_blocklen(drbg));
-	/* the test shall pass when the two compared values are not equal */
-	return ret != 0;
-#else
-	return true;
-#endif /* CONFIG_CRYPTO_FIPS */
-}
-
-/*
  * Convert an integer into a byte representation of this integer.
  * The byte representation is big-endian
  *
@@ -603,11 +561,6 @@ static int drbg_ctr_generate(struct drbg_state *drbg,
 		}
 		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 			  drbg_blocklen(drbg) : (buflen - len);
-		if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {
-			/* 10.2.1.5.2 step 6 */
-			crypto_inc(drbg->V, drbg_blocklen(drbg));
-			continue;
-		}
 		/* 10.2.1.5.2 step 4.3 */
 		memcpy(buf + len, drbg->scratchpad, outlen);
 		len += outlen;
@@ -733,8 +686,6 @@ static int drbg_hmac_generate(struct drbg_state *drbg,
 			return ret;
 		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 			  drbg_blocklen(drbg) : (buflen - len);
-		if (!drbg_fips_continuous_test(drbg, drbg->V))
-			continue;
 
 		/* 10.1.2.5 step 4.2 */
 		memcpy(buf + len, drbg->V, outlen);
@@ -963,10 +914,6 @@ static int drbg_hash_hashgen(struct drbg_state *drbg,
 		}
 		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?
 			  drbg_blocklen(drbg) : (buflen - len);
-		if (!drbg_fips_continuous_test(drbg, dst)) {
-			crypto_inc(src, drbg_statelen(drbg));
-			continue;
-		}
 		/* 10.1.1.4 step hashgen 4.2 */
 		memcpy(buf + len, dst, outlen);
 		len += outlen;
@@ -1201,11 +1148,6 @@ static inline void drbg_dealloc_state(struct drbg_state *drbg)
 	drbg->reseed_ctr = 0;
 	drbg->d_ops = NULL;
 	drbg->core = NULL;
-#ifdef CONFIG_CRYPTO_FIPS
-	kzfree(drbg->prev);
-	drbg->prev = NULL;
-	drbg->fips_primed = false;
-#endif
 }
 
 /*
@@ -1244,12 +1186,6 @@ static inline int drbg_alloc_state(struct drbg_state *drbg)
 	drbg->C = kmalloc(drbg_statelen(drbg), GFP_KERNEL);
 	if (!drbg->C)
 		goto err;
-#ifdef CONFIG_CRYPTO_FIPS
-	drbg->prev = kmalloc(drbg_blocklen(drbg), GFP_KERNEL);
-	if (!drbg->prev)
-		goto err;
-	drbg->fips_primed = false;
-#endif
 	/* scratchpad is only generated for CTR and Hash */
 	if (drbg->core->flags & DRBG_HMAC)
 		sb_size = 0;
diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h
index 9756c70..d961b2b 100644
--- a/include/crypto/drbg.h
+++ b/include/crypto/drbg.h
@@ -117,10 +117,6 @@ struct drbg_state {
 	void *priv_data;	/* Cipher handle */
 	bool seeded;		/* DRBG fully seeded? */
 	bool pr;		/* Prediction resistance enabled? */
-#ifdef CONFIG_CRYPTO_FIPS
-	bool fips_primed;	/* Continuous test primed? */
-	unsigned char *prev;	/* FIPS 140-2 continuous test value */
-#endif
 	struct work_struct seed_work;	/* asynchronous seeding support */
 	struct crypto_rng *jent;
 	const struct drbg_state_ops *d_ops;
-- 
2.5.0
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